Classifying major depressive disorders, according to TCM

In this study, researchers from Hong Kong and China investigated brain connectomic associations with traditional Chinese medicine (TCM) subtypes of major depressive disorder (MDD). The results of their study were published in the journal Chinese Medicine.

• MDD is highly heterogeneous when it comes to pathogenesis and manifestations. Scientists believe that further classification of MDD is needed to help characterize its heterogeneity.
• In their previous study, the researchers showed the differential metabolomic profiles of TCM diagnostic subtypes of MDD. Here, they continued their investigation by examining brain connectomic associations with those TCM subtypes.
• The researchers recruited 44 medication-free patients with recurrent depressive episodes and classified them into two subtypes based on TCM diagnosis. These subtypes were liver qi stagnation (LQS) and heart and spleen deficiency (HSD).
• Twenty-six patients belonged to LQS while 18 were classified under HSD. Twenty-eight healthy subjects served as controls.
• The researchers analyzed the patients’ and the controls’ whole-brain white matter connectivity using diffusion tensor imaging. They found that, compared with the other two groups, the LQS subtype showed significant differences in multiple network metrics of the angular gyrus, middle occipital gyrus, calcarine sulcus, and Heschl’s gyrus.
• Meanwhile, the HSD subtype had markedly greater regional connectivity of the insula, parahippocampal gyrus, and posterior cingulate gyrus than the other two groups. This subtype also showed microstructural abnormalities of the frontal medial orbital gyrus and the middle temporal pole.
• Insular betweenness centrality proved to be strongly inversely correlated with the severity of depression.

The researchers concluded that the LQS subtype has aberrant connectivity of the audiovisual perception-related temporal-occipital network, while the HSD subtype has hyperconnectivity and microstructural abnormalities of the limbic-paralimbic network. Based on these findings, they further concluded that insular connectivity can be used as a biomarker for TCM-based classification of depression.

Read the full study at this link.

Journal Reference:

Liu LY, Xu XP, Luo LY, Zhu CQ, Li YP, Wang PR, Zhang YY, Yang CY, Hou HT, Cao YL, Wang G, Hui ES, Zhang ZJ. BRAIN CONNECTOMIC ASSOCIATIONS WITH TRADITIONAL CHINESE MEDICINE DIAGNOSTIC CLASSIFICATION OF MAJOR DEPRESSIVE DISORDER: A DIFFUSION TENSOR IMAGING STUDY. Chinese Medicine. 11 April 2019;14(1). DOI: 10.1186/s13020-019-0239-8